function myModule(){
    // 私有的属性，外部不可见
    var msg = "sdfdf"
    function doSomething(){
        console.log(" 123 "+msg.toLowerCase())
    }

    function doOtherthing(){
        console.log(" 123 "+msg.toUpperCase())
    }

    //封装成对象返回,暴露对象
    return {
        doSomething:doSomething,
        doOtherthing:doOtherthing
    }
}